Preparation of Gold Nanoparticles Supported on TiO2 and Reactivity in CO Oxidation

Abstract:
Gold is catalytic provided that gold particles are small (<5 nm) and supported on a metal oxide. Gold supported on TiO2 exhibits remarkable catalytic properties in the reaction of CO oxidation at sub-ambient. The challenge is to achieve the preparation of small gold particles. This was done by Haruta through deposition-precipitation with NaOH (DP NaOH). An alternative method of preparation of Au/TiO2 catalysts by deposition-precipitation with urea will be presented. It leads to gold particles as small as by DP NaOH, with the advantage that all gold contained in the solution for the preparation can be deposited on the TiO2 support. Hence, the yield of deposition is high, and there is no loss of gold in solution. The catalytic behavior of these two types of catalysts in the reaction of CO oxidation will be compared. The different mechanisms of reaction proposed in the literature will be discussed to the light of our catalytic results.